import LayoutObserver from "./layout-observer";
import { mapStates } from "./store/helper";

export default {
  name: "vbtTableFooter",

  mixins: [LayoutObserver],

  render() {
    let sums = [];
    if (this.summaryMethod) {
      sums = this.summaryMethod({
        columns: this.columns,
        data: this.store.states.data
      });
    } else {
      this.columns.forEach((column, index) => {
        if (index === 0) {
          sums[index] = this.sumText;
          return;
        }
        const values = this.store.states.data.map(item =>
          Number(item[column.property])
        );
        const precisions = [];
        let notNumber = true;
        values.forEach(value => {
          if (!isNaN(value)) {
            notNumber = false;
            let decimal = ("" + value).split(".")[1];
            precisions.push(decimal ? decimal.length : 0);
          }
        });
        const precision = Math.max.apply(null, precisions);
        if (!notNumber) {
          sums[index] = values.reduce((prev, curr) => {
            const value = Number(curr);
            if (!isNaN(value)) {
              return parseFloat((prev + curr).toFixed(Math.min(precision, 20)));
            } else {
              return prev;
            }
          }, 0);
        } else {
          sums[index] = "";
        }
      });
    }

    return (
      <table
        class="el-table__footer"
        cellspacing="0"
        cellpadding="0"
        border="0"
      >
        <colgroup>
          {this.columns.map(column => (
            <col name={column.id} key={column.id} />
          ))}
          {this.hasGutter ? <col name="gutter" /> : ""}
        </colgroup>
        <tbody class={[{ "has-gutter": this.hasGutter }]}>
          <tr>
            {this.columns.map((column, cellIndex) => (
              <td
                key={cellIndex}
                colspan={column.colSpan}
                rowspan={column.rowSpan}
                class={this.getRowClasses(column, cellIndex)}
              >
                <div class={["cell", column.labelClassName]}>
                  {sums[cellIndex]}
                </div>
              </td>
            ))}
            {this.hasGutter ? <th class="gutter" /> : ""}
          </tr>
        </tbody>
      </table>
    );
  },

  props: {
    fixed: String,
    store: {
      required: true
    },
    summaryMethod: Function,
    sumText: String,
    border: Boolean,
    defaultSort: {
      type: Object,
      default() {
        return {
          prop: "",
          order: ""
        };
      }
    }
  },

  computed: {
    table() {
      return this.$parent;
    },

    hasGutter() {
      return !this.fixed && this.tableLayout.gutterWidth;
    },

    ...mapStates({
      columns: "columns",
      isAllSelected: "isAllSelected",
      leftFixedLeafCount: "fixedLeafColumnsLength",
      rightFixedLeafCount: "rightFixedLeafColumnsLength",
      columnsCount: states => states.columns.length,
      leftFixedCount: states => states.fixedColumns.length,
      rightFixedCount: states => states.rightFixedColumns.length
    })
  },

  methods: {
    isCellHidden(index, columns, column) {
      if (this.fixed === true || this.fixed === "left") {
        return index >= this.leftFixedLeafCount;
      } else if (this.fixed === "right") {
        let before = 0;
        for (let i = 0; i < index; i++) {
          before += columns[i].colSpan;
        }
        return before < this.columnsCount - this.rightFixedLeafCount;
      } else if (!this.fixed && column.fixed) {
        // hide cell when footer instance is not fixed and column is fixed
        return true;
      } else {
        return (
          index < this.leftFixedCount ||
          index >= this.columnsCount - this.rightFixedCount
        );
      }
    },

    getRowClasses(column, cellIndex) {
      const classes = [column.id, column.align, column.labelClassName];
      if (column.className) {
        classes.push(column.className);
      }
      if (this.isCellHidden(cellIndex, this.columns, column)) {
        classes.push("is-hidden");
      }
      if (!column.children) {
        classes.push("is-leaf");
      }
      return classes;
    }
  }
};
